I heard of some "experts" saying that quick and sudden decision of his was a result of reaction to the recent chemical attack, to be expected by some external beings, while his internal doings were still a mess.........? Or, it was used to show "who the boss is" to some countries.......

A nice (familiar) example is from Guilty Gear Xrd. If you look closely, the characters are 3D models rather than sprites !

Do you guys know any other Mugen characters that are made using this method ?

Yes, I once came across with this Japanese Pixel Art Shader, but I don't know how to use the 3D Blender software..........actually I rarely play with 3D models.......hope someone can make some cool 2D sprites with this Japanese tool......anyway, thank you for your tip!